1. Field of the Invention
The present invention relates generally to valve assemblies and, more specifically to, a valve assembly including a pressure relief mechanism for relieving pressure between pipes prior to opening of the valve assembly.
2. Description of the Related Art
Valve assemblies are used for regulating flow between pipes in a fluid pipeline system. Typically, these valve assemblies include a housing having a first chamber, a second chamber, and a valve seat disposed between the first chamber and the second chamber. The valve assemblies also include a valve head disposed in the housing and being moveable relative to the housing between an open position spaced from the valve seat and a closed position engaged with the valve seat.
Valve assemblies are commonly used in a fluid pipeline system that can have a bidirectional flow. When the valve head is in the closed position, the fluid can exert a pressure against a front portion and/or a back portion of the valve head to create a pressure differential between the front portion and the back portion. In one instance, when a pressure exerted on the back portion is greater than that on the front portion, the pressure on the back portion presses the valve head toward the closed position and impedes the movement of the valve head to the open position. It would be desirable to have a valve assembly capable of relieving a pressure difference between the front portion and the back portion of the valve head to reduce the force required to move the valve head to the open position.